A disseminated mycobacterial infection may mimic aplastic anemia. It is essential not to miss this diagnosis, since antimycobacterial therapy is beneficial while several therapies used for aplastic anemia can cause the patient to deteriorate..


Disseminated mycobacteriosis can result in pancytopenia and marrow hypoplasia or aplasia.


This can occur with either M. tuberculosis or one of the atypical mycobacteria.


Histologic features of a mycobacterial infection:

(1) granulomas

(2) fibrosis

(3) hemophagocytosis

(4) marrow necrosis

(5) foamy macrophages


The presence of acid fast bacilli is diagnostic:

(1) The number of organisms may be very low, so routine stains may show false negative results.

(2) Culture is useful if positive but may take some time.

(3). A molecular amplification test may be more sensitive and is quicker than culture.


Other factors to consider:

(1) history of mycobacterial exposure or infection

(2) positive response to antimycobacterial therapy

(3) exclusion of other causes


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